The specific aims of the project are to construct a safe device to cool the dental pulp and to evaluate the performance characteristics of that device in vitro. The long term objectives of this project are to determine the thermal conductivity and heat transfer capabilities of the dental pulp in relation to the surrounding dentin. Studies on the effects of lowering intrapulpal temperature on the vasculature, circulation and neurocomponents of the dental pulp will be carried out. The above investigations will lead to a method of preventing temperature increases and resultant inflammatory reactions within the pulp due to restorative procedures. The experimental design is to construct two supporting cooling systems which will contact the test teeth. CO2 coolant will be circulated through the systems to temperature level of 0 degrees celsius to 5 degrees celsius, 5 degrees celsius to 10 degrees celsius, and 10 degrees celsius to 15 degrees celsius. Each level will be cooled for a 20 minute time period in an in vitro model consisting of young first bicuspids and third molars extracted for orthodontic reasons. Temperatures will be measured by placing thermocouples to the DEJ and PDJ and placing the cooling systems in contact with all surfaces of the test tooth. Test results will provide the basis for investigations into the thermal conductivity and heat transfer mechanisms of the dental pulp and surrounding dentins as well as the ability to study the effects of temperature change (cooling) on the vasculature, circulation and neurocomponents of the dental pulp. The successful construction of the device will finally lead to a method of preventing temperature increases and resultant inflammatory reactions within the pulp as a result of restorative procedures.